The present disclosure relates to optical viewfinders capable of being attached to the bodies of cameras with interchangeable lenses capable of taking pictures of still or video images.
Japanese Patent Publication No. 2006-267380 proposes a means for obtaining a subject image through switching between an optical viewfinder (OVF) and an electronic viewfinder (EVF) in a single-lens reflex digital camera. In this publication, an image is formed by reflecting, on a mirror, a subject image transmitted through a taking lens, and then is subjected to secondary imaging near an observer with various combinations of a prism, a lens, and a mirror such that an enlarged object can be observed with an eyepiece lens. This publication also describes a means for obtaining a subject image by including an EVF panel at an optically equivalent distance to that of the surface of the secondary imaging described above and switching observation between the OVF and the EVF through driving of the mirror or a semitransparent mirror.
Japanese Patent Publication No. H06-22185 describes a camera-integrated reverse Galilean viewfinder separated from a camera lens and including a mirror and a semitransparent mirror through which an EVF panel can be observed. This configuration is intended to enable visual identification of a subject image from both of an OVF and an EVF.